Washington — Animals and plants are moving up mountainsides seeking cooler temperatures. Some fish species have smaller ranges and less abundance. Other species are diminishing in their numbers, unable to adjust to climate change, with extinction being a possible outcome.
These findings come from a wide-ranging study -- Impacts of Climate Change on Biodiversity, Ecosystems and Ecosystem Services -- produced by a collaboration of scientists from the U.S. Geological Survey (USGS), academia and environmentally oriented nongovernmental organizations.
The scientific team synthesized current understanding of how climate change is affecting ecosystems, those resources, or services, that ecosystems supply to humans or other life forms, and the diversity of life within those ecosystems. The report, released December 18, is one resource that will be used in a National Climate Assessment that is prepared by law for the president and the U.S. Congress every four years and due in 2013.
Examining climatic data from all over the United States, the report shows many shifts in rainfall, freeze dates, animal migration times and species reproduction habits. These changes are "causing cascading effects that extend through ecosystems," said Nancy Grimm, a scientist at Arizona State University in Tempe and a lead author of the study.
One key finding of the report reveals "increasing evidence of population declines and localized extinctions that can be directly attributed to climate change."
Climate changes may disrupt the delicate balance in the web of life that binds the species of individual ecosystems. Warmer temperatures might make insects emerge too early for migrating birds that rely on the newborn bugs as a food source in their seasonal travels.
Like those migrating birds, we humans could also find that climate shifts deprive us of a resource on which we depend.
"The impact of climate change on ecosystems has important implications for people and communities," said Amanda Staudt, a climate scientist at the National Wildlife Federation and another lead author on the report. "Shifting climate conditions are affecting ecosystem services, such as the role that coastal habitats play in dampening storm surge or the ability of our forests to provide timber and help filter our drinking water."
For example, frequent torrents of rain can push more pollutants downstream, changing the quality of drinking water or posing a greater threat of waterborne disease.
The purpose of the report is to inform U.S. policymakers on how these changes are unfolding domestically, but that doesn't mean these environmental changes are unique to this country.
"The sorts of climate impacts that the report details for the United States absolutely are affecting species and ecosystems around the world," Staudt wrote in response to an email inquiry. She said that some of the more than 60 U.S. scientists involved in this report consulted international studies in their research.
She cites the International Union for Conservation of Nature's Red List of Threatened Species, which has identified more than 4,000 species threatened by increased temperatures, harsher droughts and other climate-related shifts in habitat. The research shows temperature extremes affecting 29 percent of the 4,000 species studied and droughts affecting 28 percent.
The U.S. research shows that climate change is shifting the abundance and geographic range of commercially important ocean fish. "These changes will almost certainly continue," said Michelle Staudinger, a USGS scientist and lead author, "resulting in some local fisheries declining or disappearing while others may grow and become more valuable," if the fishing industry can find an acceptable way to adapt to change.
Impacts of Climate Change also finds with high certainty that climate change is a top cause of wildfire and tree insect outbreaks that are killing forests in the western United States.
"Profound changes in snowpack," the timing of melting, and the frequency of soil freezing are also causing serious consequences for land and water ecosystems in mountains and adjoining lowlands, the report finds.
Identifying ways to adapt is vital for the conservation of diverse species and effective management of natural environments by human environmental caretakers, the report says. "The conservation community is grappling" with how to achieve that end, said contributing author Bruce Stein, director of climate adaptation at the National Wildlife Federation.